CHAPEL HILL, N.C. — A professor at the University of North Carolina at Chapel Hill has identified variants of the virus that causes AIDS depending on where in the body the virus is found

In a paper to be published in the online journal PLoS Pathogens, , calls the differences between HIV-1 in the blood and the virus in semen "like a flashing red light."

The finding is important to further study of how the virus is transmitted and treated, since most HIV infections worldwide occur via seminal fluid.

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